Sacroiliac (SI) joints are located between the sacrum and the right and the left iliac bones, respectively. The SI joints provide support for the entire weight of the upper body when a human stands erect, which creates a large amount of stress on the SI joints. Therefore, these joints are susceptible to injury and degeneration. Acute and chronic injury, degeneration, and laxity of the supporting ligaments of the SI joint can result in low back and radiating buttock and leg pain in afflicted patients. Stabilization or immobilization (fixation) of the SI joint is commonly advocated as a surgical treatment for many SI joint disorders.
A significant problem with certain conventional methods for SI joint fixation is that they require a surgeon to have direct access and a view of the SI joint. Thus, some conventional SI joint fixation techniques require the use of what is commonly referred to as “open surgery,” and result in significant trauma and disruption to the tissues and skin surrounding the SI joint. Open procedures increase the risk of damage to major nerves, blood vessels, ligaments, and muscles around the incision site. Moreover, open procedures increase operative, hospitalization, and recovery time due to the extensive soft tissue damage resulting from open surgery techniques.
In response to the problems related to open surgery for SI joint fixation, minimally invasive surgical (MIS) procedures were developed. Currently, one of two approaches is taken to access the SI joint for fixation procedures: a lateral approach and a posterior approach. In conventional MIS procedures employing the lateral approach, screws, rods, or other fixation devices are passed through a small incision (as compared to that in open surgery) made on the lateral hip and inserted laterally through the ilium, across the SI joint space, and into the sacrum. See, e.g. U.S. Pat. No. 8,221,428 by Trieu.
Alternatively, a posterior approach may be used to access the SI joint for delivery of SI joint implants. See, e.g. U.S. Publication No. 2012/0316565 by Stark and U.S. Publication No. 2013/0035723 by Donner. In the posterior approach disclosed by Stark and Donner a small (as compared to that in open surgery) incision made in the patient's back, and the SI joint is accessed through an extra-articular recess located between the sacrum and the ilium.
Although the points of incision are different in current MIS procedures for accessing the SI joint, neither is truly minimally invasive. Conventional lateral MIS procedures still may result in significant trauma to the major nerves, blood vessels, and muscle groups of the hip. While current posterior MIS approaches eliminate damage to the soft tissues and neurovascular system of the lateral hip, they still carry a significant risk of trauma to the spinal nerves and major back and hip ligaments.
There exists a need for improved MIS procedures and devices that are less invasive and decrease soft tissue trauma and the risk to neurovascular tissue during SI joint fixation procedures.
Therefore, it is an object of the invention to provide an improved, less invasive method for implanting a fixation device in the SI joint.
It is further an object of the invention to provide an improved SI joint implant device with decreased risk of trauma to surrounding tissues during implantation.